1. Field of the Invention
The present invention relates to a glass substrate including a grooved portion formed in a micron structure in a terrace-shaped flat portion formed on a substrate, such as a micro-reactor chip, a substrate for microanalysis or an optical fiber fixing substrate, a method for fabricating the same, and a press mold for fabricating the glass substrate.
2. Discussion of Related Art
In the field of optical communication, there has been known an optical fiber fixing substrate, which brings opposed end portions of optical fibers into alignment with each other and fixes both opposed end portions for connection of plural optical fibers or plural optical fibers and other elements, such as light guides (for example, JP-A-11-194226, pages 5 and 6, FIG. 1 and FIG. 4).
This optical fiber fixing substrate includes an optical fiber engaging portion having V-shaped grooves formed therein to engage (put) opposed end portions of optical fibers therein, and stoppers for adhesive flow formed both sides of the optical fiber engaging portion, wherein the end portions of the optical fibers are engaged with the optical fiber engaging portion, and an adhesive is filled in the optical fiber engaging portion, and a pressing member is covered from above the optical fiber engaging portion to fix the end portions of the optical fibers between the optical fiber fixing substrate and the pressing member. In this case, the adhesive, which is filled in the optical fiber engaging portion, can be prevented from leaking out of the optical fiber engaging portion by the provision of the stoppers for adhesive flow.
This optical fiber fixing substrate is made of glass. The substrate is fabricated by being pressed by a forming mold, which is ground by a grinding wheel. Additionally, the tops of the V-shaped grooves are chamfered in an arcuate shape.
Although the optical fiber fixing substrate disclosed in JP-A-11-194226 has the tops of the V-shaped grooves chamfered in an arcuate shape, the other portions of the substrate are not chamfered. Since there is a possibility that any one of the other portions is inadvertently chipped to damage an optical fiber, there is a problem that handling is difficult. Since the optical fiber fixing substrate disclosed in JP-A-11-194226 has only the tops of the V-shaped grooves chamfered, there is another problem that any one of the tops is likely to be chipped when contacting another member.
By the way, a micro-reactor chip or a substrate for microanalysis has been known as a substrate comprising a glass substrate base material having grooves formed in a micron structure (in microns), such as an optical fiber fixing substrate. Such a micro-reactor chip or such a substrate for microanalysis has a flat portion formed with grooves in microns for flowing a solution and has a problem that trouble is caused in reaction or analysis when a groove is chipped. Additionally, it is necessary to strictly control a flow rate in these applications. Although a cover, such as a glass sheet in a flat shape, is put over the grooves for forming flow passages, there is a possibility that a flow rate fails to be sufficiently controlled unless the flat portion in addition to the shape of the grooves has necessary molding precision.